Digitization at UNC-Chapel Hill

At UNC-Chapel Hill, maps are digitized in the Digital Production Center in the Carolina Digital Library and Archives. Maps up to 11" x 17" are digitized on a flatbed scanner, while larger maps are digitized using the vacuum frame and camera back described here. This equipment was purchased for the North Carolina Maps project with funds provided through a Library Services and Technology Act grant distributed by the State Library of North Carolina and NC ECHO.

Vacuum Frame

Maps are imaged by placing them within a 4’x 5’ Teaneck Vacuum Frame (an industrial graphic arts tool). This frame sandwiches the map between glass and the back of the frame. Once switched on, the vacuum removes the air, ensuring the map is completely flat during image capture.

Lisa Gregory secures a map in the vacuum frame. Photo by Fred Stipe.

Lights

Digitization

Maps are scanned using a hybrid imaging system. A BetterLight Large Format Digital Scanning Camera Back, Model Super 8K-HS, is used with a Horseman 450XL 4”x5” studio camera and a Rodenstock APO-Sironar Digital 180mm f/5.6 lens. The system is mounted on a Cambo UST studio stand. The distance between the stand and the vacuum frame is adjusted depending on the size of the map.

BetterLight Digital Scanning Camera Back. Photo by Fred Stipe.

Maps are captured at 100% of their original size, 300pixels per inch using the TIFF file format. File sizes typically range in the hundreds of megabytes.

Scan times are usually between 3.5 and 7 minutes.

All post-capture work is done on a Mac Pro with dual Intel processors using Adobe PhotoShop CS3.